In this worksheet, students look at how energy doesn't come from nowhere, and how energy isn't lost....but rather changes forms in a system. Students work through examples such as a flashlight that's been turned on, a moving foot kicking a soccer ball. Seven of these type of problems are included.
In the worksheet, I use the CEMENTS list of types of energy:
The worksheet also includes a problem about a bouncing ball that focuses on mechanical energy (kinetic, potential gravitational, potential elastic), as well as a problem that ties the two types of problems together (looking at why a roller coaster has progressively lower hills).
The worksheet includes an answer key, and is in Word format.
You're more than welcome to edit the document to suit the needs of your students, and your teaching style.
Please let me know of any improvement you feel I could make!